A couple of thoughts. Has the lovely lady told you to check Home Point on the map? Wondering if the extra few seconds between trying to manually spin up the motors then going to the screen to auto take off enough satellites are connected. Also, once you land and the motors stop, have you then tried a manual motor start then a take off?
The other thought is the problem is with the Flight Controller and the "down and in stick" simultaneous movement isn't being recognized so try a stick calibration in the app. If that fails maybe try doing the other optional movement to start the motors, a "down and out" movement with both sticks (as shown in my thumbnail in my previous post above).
Anybody else have any ideas??